We are interested in characterizing the chemicals responsible for the axillary and scalp odor and in correlating the presence or absence of these chemicals with a particular bacterial population in both in vivo and in vitro studies. A study will be made of the chemical nature of apocrine secretion, the odor generated upon heating the secretion and its use as a substrate for skin microorganisms. Analysis will involve concentration of the odor chemicals on an organic polymer and their subsequent separation and identification by gas chromatography-mass spectroscopy. This approach has been successfully used for the determination of an in vitro odor profile of P. ovale, a major scalp microorganism. Such an odor profile may serve as an additional aid in classification of microorganisms. It is hoped that an understanding of the interaction of skin microorganisms and body secretions will provide alternate methods of odor control and of disease diagnosis in cases which involve changes in body odors.